Milling apparatus.



E. H. MARTIN. IMILLING APPARATUS.

APPLICATION FILED JULY 6, 1909.

976,585. V I Patented Nov. 22, 1910.

rue: uorems PETERS cm. WASHINGTON, n. c.

ERNEST HOLROYD MARTIN, OF JOHANNESBURG, TRANSVAAL.

MILLING APPARATUS.

T 0 all whom it may concern:

Be it known that I, MARTIN, battery manager, a subject of the King of Great Britain, residing at the Langlaagte Estate and Gold Mining Company Limited, Langlaagte, Johannesburg, Transvaal, have invented certain new and useful Improvements in Milling Apparatus, of which the following is a specification, reference being had therein to the accompanying drawing.

The present invention relates to the milling of ore and like substances in stamp batteries or other reducing machinery of the class which receives ore mainly as irregularly sized lumps and discharges it usually through a screen, principally in the form generally designated as sands.

According to this invention, after the ore has passed through all the prior steps that are necessary or desirable e. 9., sorting, breaking and passing through the bins, so that no further comminution will occur, and immediately before it passes into the milling machinery, itis graded so as to remove from it all material which is equal to or less than the maximum size which the milling machinery is designed to produce.

A suitable device for carrying out the invention is shown in the accompanying drawings, of which-- Figure I is a detached perspective view and Fig. II is a transverse section through the device and through the mortar boX to which it is fitted.

The device includes a .box-like structure 1 formed with an angular bottom 2 sloping toward one end 3. The top of the box is covered with an inclined grizzly 4: preferably of the improved construction shown. In

such improved grizzly a number of compara-' tively narrow bars 5 are situated horizontally and stepped down from one another; the vertical spacing between the bars being somewhat greater than the horizontal spacing. This formation obviates obstruction of the grizzly since any lumps which are only slightly larger than the horizontal spacing of the bars and would therefore tend to lodge in said spaces were the grizzly surface plane, are afforded an opportunity to pass by fall.- ing backward through the somewhat larger vertical spaces. The grizzly bars may be held in place on top of the box by means of a frame 6 bolted to the box.

Below the grizzly is placed an inclined Specification of Letters Patent.

Application filed. July 6, 1909.

Patented Nov. 22, 1910.

Serial No. 506,191.

screen 7, the mesh of which is equal to that ERNEST I-IoLRoYD of the battery screening 8. Said screen is mounted upon a frame 9 and is passed into place through a slot 10 in the side of the box 1 so that it may be removed when required for repairs or otherwise. The upper edge 11 of the frame 9 is beveled in order to carry the wire fabric as closely as possible to the back of the box. Material passed off the screen is carried by a lip 12 clear of the box. A door 13 is provided in the side of the box to permit the screen to be swept and inspected from time to time.

14 represents a perforated pipe from which a water spray is delivered over the grizzly to assist separation and conveyance of the material.

15 indicates a pipe by which pulp collected in the pointed bottom 2 is conveyed around the mortar box 16 and distributed onto the amalgam plate 17 or otherwise disposed of as may be thought desirable.

Immediately beneath the grizzly is arranged a cut-ofi device consisting of the two pivoted leaves 18 and 19 which are provided externally of the box with actuating levers 20 and 21 respectively. Lever 21 is cranked at 22 to form a handle; said handle being adapted when swung up to engage lever 20 and so cause both levers to be closed simul taneously. 23 represents a catch which engages lever 21 to hold the leaves in the closed position. WVhen hanging normally as shown in Fig. II leaf 18 shields the upper edge of the frame against falling ore, while leaf 19 directs ore which falls onto it to the upper part of screen 7. The handle 21 may be provided with an extension 2 1 which prevents withdrawal of the screen 7 while the leaves 18 and 19 are open.

In fitting up the above described device it is attached to the mortar box 16 so that the lip 25 at the lower edge of the grizzly overhangs the usual feed opening 26, while a special aperture 27 is cut to receive material from the screen 7.

In operation all material fed from the feeder 28 falls onto the grizzly, from which the larger lumps roll directly into the mortar box feed opening 26. Such material as passes through the grizzly is received by the screen 7 which passes material oversize to the battery screen into the mortar box through aperture-27 but permits the undersize to continue through into the pointed bottom whence it is conveyed by the stream of water, supplied by pipe 14, through the pipe 15 and so distributed onto the amalgamating plate. 17 or otherwise disposed of as may be desired.

When it is required to repair or inspect the screen 7 the leaves 18 and 19 are turned up into place under the grizzly, whereby all the ore is passed directly into the mill without separation.

VVha-t I claim, and desire to secure by Letters Patent is 1. In combination with ore milling machinery provided with discharge screening, a grizzly onto which the ore is fed, a screen of equal mesh to the mill screening and adapted to receive matter passing through the grizzly, said grizzly and screen feeding their oversize to the milling machinery, means for collecting material which passes through the screen, and adjustable means whereby the whole of the ore may be passed directly to the milling machinery.

2. In combination with a stamp battery having a mortar box provided with discharge screening, a grizzly onto which the ore is fed, an inclined screen of equal mesh to the mill screening and adapted to receive matter passing through the grizzly, said grizzly and screen feeding their oversize to the mortar box, means for collecting mate rial which passes through the screen, and adjustable means for closing the grizzly, said means normally serving to direct the grizzly undersize onto the upper part of the screen.

3, In combination-a mortar box, provided with the usual open topped feed channel,

said channel being formed with an auxiliary feed aperture, a casing located adjacent to the feed opening thereof, an inclined grizzly at the top of the casing onto which ore is fed and which passes its oversize over the lip of the feed channel, an inclined screen mounted upon the casing under the grizzly, which screen passes its oversize through said auxiliary aperture, said casing being continued below the screen to collect the undersize therefrom.

4. The combination with a mortar box having an open topped feed channel, said channel being formed with an auxiliary feed aperture, of a stationary casing located on one side of the mortar box adjacent to said auxiliary feed aperture, an inclined grizzly rigidly secured in position at the top of said casing and discharging its oversize into said feed channel, an inclined screen rigidly mounted in the casing below the grizzly and discharging its overslze through said auxiliary feed aperture, said casing having a closed-in inclined bottom, a discharge screening rigidly secured in the outlet from the I mortar box, means for conveying material I l 1 from the lower end of said casing around the mortar box to a point outside the dis charge screening and means for discharging water upon the grizzly. In testimony whereof I afiix my signature i in presence of two witnesses. ERNEST HOLROYD MARTIN.

Witnesses:

ALFED L. SrooR, l WEsLEY A. J OHN. 

